I realise this wouldn't be for everyone, but it's really made a positive difference for us.
Before:
16yo dd moping about saying she can't face breakfast.
14yo ds in the kitchen frying eggs and making a mess.
10yo dd eating her body-weight in sugary crap cereal.
So I changed it a bit and now when everyone gets up (about 20 minutes after me) breakfast is out on the table. I do something different every morning, it's very simple, no choice, just sit down and eat what's there. They love it!
This week was:
M - croissants and jam and milo
T - porridge and fruit
W - brioche toast
Th - Yogurt and fruit
F - Eggy bread
I put out a hot drink, a bottle of OJ or water, and their vitamins.
It takes me 5 minutes, and they clear it all up when they're done. Everyone has been so much more cheerful in the morning. I've been doing it for a few weeks now - I include 5 simple breakfast choices along with my big weekend shop. It hasn't cost any more. The teens have even been getting up to join in breakfast on flexible learning days (when they don't have to be at school).